Continuous cellulose pulp digester



May 31, 1960 J. DE LA ROZA, SR. ET AL 2,938,580

commuous CELLULOSE PULP DIGESTER Filed April 2, 1953 12 Sheets-Sheet 2INVENTORS. .6424

May 31, 1960 J. DE LA ROZA, sR., l-rrAL 2,938,580

coNTINUous CELLULOSE PULP DIGESTER 12 Sheets-Sheet 3 Filed April 2, 1953H 5% [lg INVENTORS.

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May 31, 1960 J. DE LA ROZA, SR., ETAL CONTINUOUS CELLULOSE PULP DIGESTER12 Sheets-Sheet 4 Filed April 2, 1953 INVENTORS. AXG'Q JQ. ma r.

May 31, 1960 J. DE LA ROZA, SR, ET AL 2,938,580

CONTINUOUS CELLULOSE PULP DIGESTER l2 Sheets-Sheet 5 Filed April 2, 1953JNVENTORS. M W.

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May 31, 1960 J. DE LA ROZA, sR., ET AL 2,938,580

cou'rmucus CELLULOSE; PULP DIGESTER Filed April 2, 1953 12 Sheets-Sheeta 1 1 I V 9 a k 3 May 31, 1960 J. DE LA ROZA, SR, ETAL 2,938,580

CONTINUOUS CELLULOSE. PULP DIGESTER Filed April 2, 1953 12 Sheets-Sheet'7 IN V EN TORS.

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ATYLRNEY? y 31, 1960 J. DE LA ROZA, SR, ETAL 7 2,938,580

CONTINUGUS CELLULOSE PULP DIGESTER Filed April 2. 1953 12 Sheets-Sheet 8I N V EN TORS.

May 31, 1960 J. DE LA ROZA, sR., ETAL commucus CELLULOSE PULP DIGESTER12 Sheets-Sheet 9 Filed April 2, 1953 INVENTORS.

ATTORJEYS May 31, 1960 J. DE LA ROZA, SR, ETAL 2,938,580

CONTINUOUS CELLULOSE PULP DIGESTER Filed April 2, 1953 12 Sheets-Sheet11 May 31, 1960 J. DE LA ROZA, SR., ETAL 2,938,580

commuous CELLULOSE PULP DIGESTER Filed April 2, 1953 12 Sheets-Sheet 12INVENTORS.

MAJ'Z'ORNEYS CONTINUOUS CELLULOSE PULP DIGESTER Joaquin de la Roza, Sr.,White Plains, and Joaquin de la Roza, Jr., New York, N'.Y.; said Joaquinde la Roza, In, assignor, by mesne assignments, to said Joaquin de laRoza, Sr.

Filed Apr. 2, 1953, Ser. No. 346,368

20 Claims. (Cl. 162-244) This invention relates to apparatus for thecontinuous digestion of cellulose bearing material to produce acellulose pulp of any degree of purification suited for use in themanufacture of board, paper and a multitude of products having celluloseas their base or as an important component.

An object is to produce such an apparatus which is designed and adaptedfor digesting treatments of extended duration and in large volume, underappropriate conditions with relation to pressure, temperature, andchemical action; the apparatus eliminating the restrictions,inconvenience, and lack of uniformity of batch treatment, as well as thesmall output and structural and mechanical defects or drawbacks thathave attended previous efforts in the direction of continuous treatment,while avoiding excessive construction cost and complication andattaining such a degree of automaticity, reliability and uniformity infunctioning as sharply to reduce supervisory expense and maintenance.

Another object is to produce such an apparatus which embodies combinedmaterial feeding and impregnating means and mechanism that serve to forma pressure resisting cork for the digesting chamber inlet, provide foreffective removal of excess treating liquid and other fluids or gasesfrom the material as it forms the cork, and permit ready forwardmovement and ejection of the cork from the inlet into the digestingchamber regardless of the density or hardness of the cork.

Another object is to produce such an apparatus of which the inlet isfitted with novel means for restricting its cross sectional area inorder to impede to a predetermined extent the forward motion of thematerial and thereby form a cork of desired density, the restrictingmember being activated in its closing movement by fluid pressurethereupon and being restrained as to the extent of its opening movementby an adjustable element.

Another object is to produce such an apparatus that has a hopper, or thelike, for supplying the material to the feeding means, and in whichthere is associated with the hopper an arrangement for wetting and atleast partially impregnating the material with treating fluid.

Another object is to produce such an apparatus which comprises inner andouter cylindrical chambers, the inner constituting the digesting chamberand the outer serving to establish a heating jacket surrounding theinner; together with means for simultaneously rotating both chambers tofacilitate thorough and uniform admixture and impregnation of thematerial with treating liquid, uniform exposure to temperature andpressure conditions, and travel of the material through the apparatus.

Another object is to produce such an apparatus as described in thepreceding paragraph which also includes provisions to allow for relativelongitudinal expansion of the cylindrical chambers while resistingrelative torque thereof.

Another object is to provide such an apparatus with improved connectionsbetween the fixed inlet and discharge structures and the rotatingdigesting chamber,

United States Extent chamber and re WC whereby a yielding, adjustableseal is established, and the ends of the apparatus are fitted with meansto resist longitudinal thrust due to pressure.

Another object is to produce such an apparatus which includes meansconnecting or tying together the fixed inlet and discharge structures soas effectively to withstand the longitudinal thrust generated bypressure within the digesting chamber.

Another object is to fit such an apparatus near one or both ends withconstantly effective safety and relief devices for air, gas and liquid,to prevent injury to the apparatus; said devices preferably beingequipped with suitable instruments for indicating and/or recording andenabling control of such factors as pressure, temperature, materiallevel, as well as others normally incident to the treatment involved.

-Another object is to provide improved means for rotatably supportingand driving the digesting chamber without in any way disturbing itsoperative relationship with stationary pants.

Another object is to include in such apparatus improved rneans for thesupply of heating steam, and for removal of condensate; the latterinvolving valves, or the like, peripherally positioned on the digestingchamber and complementary means for coacting with a valve when itapproaches a low point in the cycle of rotation of the chamber,together, preferably, with means for controlling the functioning of thesaid valve.

' Another object is to associate with such an apparatus a controlsystem, preferably electric, for discontinuing the motor drive of thedigesting chamber and bringing the apparatus to rest if the longitudinalmovement of the chamber exceeds desired operational Another object is toconstruct such an apparatus with improved features at the discharge endwhereby efliciency in operation is attained and maintenance reduced.

Another object is to provide the interior of the digesting chamber withan helix, worm, screw, or the equivalent, for causing the material beingtreated to.travel a longer path during treatment without increasing thelength of the apparatus; provision also being made for the escape ofair, gas and vapor past the helix, worm or screw and the venting thereofpromptly after liberation or forming through an appropriate reliefdevice.

Another object is to produce such an apparatus which is admirably suitedto arrangement and interconnection with one or more similar units,coupled with appropriate and suitable intermediate elements, for thepurpose of plural step digestion, such, for instance, as a firsttreatment, with or without the addition of chemical, and a secondtreatment with the addition of alkali.

A further object is to provide certain improvements in the form,construction and arrangement of the several parts of the apparatuswhereby the above named objects and others inherent in the invention maybe effectively attained.

The subject matter of this invention, generally considered', comprises arotatable digesting chamber, either jacketed or not, with improved andnovel means for performing the following functions: feeding the materialto be digested, usually wet with chemical solution, into the chamber;removing excess liquid, air, and other fluids and gases from thematerial as it is fed; regulating the feeding opening to form thematerial into a cork of desired density; providing for longitudinalexpansion of the chamber while maintaining proper alignment of thejacket; supporting and rotating the chamber and jacket; supplying steamto the jacket space or steam, Water and chemical to the interior of thechamber; automatically removing condensate; yieldingly and adjustablysealing the contacting end portions of the rotatable digesting chamberand the fixed inlet and dis-.

assessocharge structures of the apparatus, and preserving the seal inspite of circular wobbling motion of the chamber with respect to thefixed structures due to departure of the chamber axis from precisealignment with theaxis or either or both said fixed structures; causingthe material to follow either a straight or elongated spiral paththrough the chamber while permitting escape "of air and gases;automatically stopping the drive of the chamber in the event oflongitudinal movement beyond a predetermined" limit; and discharging thetreated material from the chamber.

. The various elements of the apparatus just summarized, together withtheir functions, will be explained at length and their novelty'andimproved characteristics will be more clearly presented in conectionwith the detailed description to follow the identification of thefigures of the drawings which exhibit a plurality of embodiments of theinvention, and in which Figs. 1, 1a and 1b represent collectively abroken side elevation, partly in section," of the form of the inventionwhich embodies a jacketed digesting chamber for the purpose of suplyingheat to'the exterior of, the chamber;

Fig. 2 represents an end elevation of Fig. 1b, looking from right toleft I i Fig. 3 represents an enlarged detail transverse section takenin the plane of the line III of Fig. 1b, looking in either direction; I

Figs. 4, 4a and 4b represent collectively a view similar to Figs. 1, 1aand 1b but showing a modified form of the invention embodying anunjacketed digesting chamber to the interior of which heat is supplied;

Fig. 5 represents an enlargeddetail, vertical, longitudinal, centralsection, partly in elevation, of the right hand end portion of Fig. 1b;

Fig. 6 represents an enlarged transverse section taken 1 partly .ing inthe direction of the arrows, and showing the distion, showing an helix,worm or screw which may be in the plane of the line VI-VI of the Fig.In, looking in either'direction;

Fig.7 represents an enlarged detail transverse section taken in theplane of the line VII of Fig. 1a, looking in either direction;

Fig. 8 represents a detail section taken in the plane of the lineVIII-VIII of Fig. 7, looking in either direction;

Fig. 9represents a view similar to Fig. 7, but somewhat more complete,showing a modified form of structure; 1

Fig. 10'representsa view similar to Fig. 8, but showing the modifiedstructure of Fig. 9;

Fig. 11 represents an enlarged detail section, partly in elevation,taken in the plane of the line XI of Fig. lb, looking in the directionof the arrows;

Fig. '12 represents an enlarged detail, vertical, central sectiompartlyin elevation, of the material supplying hopper and crankoperated piston.shown in Fig. 1;

Fig. 13 represents an enlarged detail, vertical, central section partlyin elevation, of the adjustable check or iqonstrictor-for the digestingchamber inlet shown in Fig. 14 represents an enlarged detail section ofthe pivotal mounting and gasket for the said check or con strictor;

Fig. 15 represents a transverse section taken in the plane of the lineXVXV of Fig. 13, looking in the direction of the arrows;

Fig. 16 represents an enlarged detail, vertical, longitudinal, centralsection, partly in elevation, of the sealing construction, thrustresisting construction and pressure releasing dome at the inlet end ofthe apparatus;

Fig. 17 represents a transverse section, partly in elevation, taken inthe plane of the line XVII-XVII of Fig. 16, looking in the direction ofthe arrows; 7

Fig. 18 represents an enlarged detail longitudinal section throughtheupper part of the bellows and'adjacent parts shownin Fig. 16;

Fig. 19 represents an enlarged, vertical, transverse sec tion, taken inthe plane of-the line XIX-oi Fig. 1b, lookmounted within the digestingchamber for causing the material being treated to travel a longer path;

Figs. 25 and 25a represent collectively a broken, detail, side elevationof the form of the invention which embodiesan' unjacketed digestingchamber, with a modification directed to the provision of external meansfor connecting or tying together the fixed inlet and dischargestructures for the purpose of withstanding longitudinal thrust generatedby pressure within the digesting chamber;

Fig. 26 represents a transverse section, partly broken away, taken inthe plane of the line XXVIXXVI of Fig. 25, looking in the direction ofthe arrows;

Fig. 27 represents a detail perspective view of the central support forthe external connecting or tying'means;

Fig. 28 represents a detail sectional view, partly in elevation, of theform of the invention which embodies an unjacketed digesting chamber andincludes an helix, worm or screw, as also illustrated in Fig. 24, thesaid Fig. 28 exhibiting a further modification directed to the provisionof internal axial means for connecting or tying togethe the fixed inletand discharge structures; and

Fig. 29 represents a detail section taken in the plane of the lineXXIXXXIX of Fig. 28, looking in the direction of the arrows.

Proceeding now to a detailed description of the invention, andconsidering all the figures of the drawings, with the exception of Figs.4, 4a, 4b, 24 to 28, which exhibit the modified forms; the apparatusincludes a feeding inlet 1 (Figs. 1 and 12), that is generallycylindrical inform but is provided with flanges 2, 3, at the lowerportion of each side thereof for firmly securing the inletby cap screws4 to the top 5 of a sturdy, rigid base 6, which; may desirably be ofsteel and concrete construction. Formed in the top of the inlet is aflanged opening7 to which is bolted a material supply hopper 8, that hasan open top into which may be dumped, as by traveling belt or the like,the cellulose bearing material, e.g., bagasse, wood or other analogoussubstances. The upper edge of the hopper is surrounded by a pipe 9 whichis fitted with suitable connections for receiving fluid and hasperforations along its inner periphery coinciding with holes through thewall of the hopper so that any desired fluid, such for instance aswater, chemical solution, or steam, may be sprayed upon the incomingmaterial.

The side of the inlet 1 away from the digesting chamber (to the left inFigs. *1 and 12), is bored, as indicated at 10, slidably to receive acharging piston 11 which is fastened by cap screws, one of which isshown and marked 12, to a crank'head 13, that is connected by a pitman14, toappropriate rotary-reciprocating .mech anisrn, denoted generallyby 15, that is mounted on the base 6 and powered by a motor 16, with theprovisionof suitable variable speed. reduction intermediate drivingconnections that are illustrated in Fig. 1, but will not be described indetail as they; per se, constitute no part of the present invention. Thecrank head 13 has gibs, one being shown and marked -17, screwed to itslower side edges, which ride in undercut rails (one of which is shownand marked 18) on the top of base 6, to guide the reciprocation of thecrank head.

bore of; the inlet 1, sufiicientto permit the passage of liquid, and thesaid bore is surrounded by an annular rim 19 which is cut away toconstitute a small chamber 20, which communicates at its bottom with apipe 21 that may lead to a disposal point or to a connection for reuseor recovery. The chamber 20 is sealed around the piston 11 by a gland 22which is adjustably secured to rim 19, and is itself rendered fluidtight by a stufling 23, clamped in place by another gland 24, which isadjustably fastened to gland 22. The construction just explained is ofnotable value in that it provides for the automatic removal of excessfluid from the material being treated as the latter is compressed by thepiston, and hence permits the use of a maximum amount of fluid formixing with the material as it enters the hopper 8, thus tending toinsure complete impregnation. At the same time, the clearance betweenthe piston and the hopper bore in which it lies is not sufilcient topermit passage of solids and, in effect, serves as a strainer whichnever clogs.

As the impregnated material falls downwardly through the hopper into theinlet 1, it is compressed by the reciprocating piston and forms a corkin the inlet which resists the pressure generated in the digestingchamber during operation, the said cork composed of the material beingcontinuously forced through the inlet and into the digesting chamber fortreatment therein; and being likewise continuously renewed; so thatthere is a constant ingress of the material for digestion and themaintenance of a cork or plug to withstand the back pressure from thedigesting chamber. In this connection, an important feature relative tothe form of the inlet 1 resides in the fact that the diameter, or crosssectional area, of the interior thereof increases in the direction fromthe hopper 8 toward the digesting chamber, thereby obviating a seriouspreviously existing drawback attendant upon the use of an inlet ofopposite form, i.e., one that tapered rather than flared in thedirection toward the digesting chamber. It has heretofore been regardedas necessary to employ such a taper in order to insure the formation ofthe above mentioned cork, but the result has been the frequent formationof a cork of such density or hardness that it could not be forcedthrough the inlet, and required stoppage of operations and hours, oreven days, devoted to breaking up and removing the cork. We havedetermined that the flaring or increasing cross-sectional form of ourinlet eliminates this previous trouble, and we insure the establishmentof a satisfactory cork of predeterminable density by the provision of aproperly adjustable constriction throat which intervenes between theinlet 1 and the digesting chamber, and will now be described.

Referring to Figs. 1 and 13-15, the constriction throat is denotedgenerally by 25. Its body is quadrangular in cross section, but its endsare in the form of circular flanges 26, 27, which are fastened by studbolts (some of which are shown and marked 28, 29) to mating flanges 30,31, on the inlet 1 and the neck of the digesting chamber. A centralexternal flange 32, and connecting external web shown in the drawingsbut which it is not deemed necessary to number, serve to strengthen thethroat, and the lower part of flange 27 is projected in the form of afoot 33 to rest upon a suitable base support A constrictor 35, which istapered longitudinally and rectangular in cross section, is pivoted in acurved socket recess 36 at its small end within the throat 25 so as toswing upwardly and downwardly therein, as indicated by the full andbroken lines in Fig. 13; while a stop 37 is threaded in the upper wallof the throat at 38, and housed within a sleeve 39 projecting upwardlytherefrom, adjustably to limit the upward swing of the constrictor. Theprotruding upper end of the stop is shaped for the application of anadjusting tool. The constrictor may thus be held in proper contact withthe material passing through the throat 25 and resist its movement toinsure the formation of a satisfactory cork by, in effect, reducing thecross section of the interior of the throat. To continuously urge theconstrictor 35 downwardly, any appropriate fluid, e.g., or steam, underregulatable pressure from a suitable source, is injected through a pipe40 which enters an orifice in flange 31. This pressure will serve tomove the constrictor 35 all the way down and close the throat 25 in theevent the material cork is dissipated, as by chemical action, therebypreventing material under pressure in the chamber from returning to theinlet 1. A sealing gasket 41 is fitted in a groove surrounding the lowerpart of the constrictor; and a packing gland, denoted generally by 42,prevents leakage around the stop 37. Removable plugs 43, 43, arepreferably provided for cleaning the space in the throat that houses theconstrictor.

'The neck of the digesting chamber to which the throat 25 is fastened asjust described, and with which it communicates, is composed of two parts44 and 45, which are rigidly secured together by flanges 46, 47, andbolts 48 (Fig. 16). The bore of the neck is somewhat greater in crosssection than that of throat 25, so that, as the material being treatedpasses from the latter to the former, a certain amount of expansion ispermitted which eases and facilitates the flow. In the. top of part 44of the neck is fitted a pipe 49 adapted for connection with a conduit 50that leads from asource (not shown) of treating fluid, e.g., chemical,so that a regulated amount thereof may be added to the material at thisjuncture if desired. Any approved form of valve control may be providedfor regulation. The part 45 of the neck is formed at the upper portioninto a collar 51 designed for communication with a relief dome 52, theparts being connected by flanges 53, 54, and bolts 55; and the dome issurmounted by a rupture diaphragm unit, indicated generally by 56, whichmay be of any appropriate form and construction calling for no furtherillustration or description because well known to engineers, the unitbeing secured in position on the dome by flanges 57, 58, and bolts 59. Avent is also provided at one side of the dome near its top. In thedrawings the dome is shown in broken view with respect to its height andit should be stated that the exact height is not a matter of importanceprovided it is suflicient to permit a level of contents at least as highas (preferably higher than) the highest level of the contents of thedigesting chamber. The lower portion of the part 45 is likewise formedwith a collar 61 which extends downwardly and is fitted with a removablebolted cover 62 for drainage and cleaning purposes. The dome 52 isequipped at or near its top with instruments of any standard or suitableform (not shown) for indicating, measuring and/or control-ling digestingchamber pressure, temperature, material level, relief, and other desiredfactors, which are of value not only for management of the digestingtreatment but also for safety. It will thus be seen that the dome 52 andits accessories are designed as automatic safety means and also as meansfor operational control. To the forward end of part 45 of the neck isfast, preferably integrally or by welding, a sturdy annular frame 63,the lower portion of which finds support on a well braced foot 64 thatrests upon a foundation base at 65, thus cooperating with the parts 6and 33-34 in sustaining the elements or members of the apparatusheretofore described in fixed, rigid alignment.

An important aspect of the invention is the structure that unites thesefixed parts with the rotating digesting chamber While maintaining asubstantially perfect seal, which structure will now be described, withreference to Figs. 1048.

A cylindrical cover 66 is fixed to the forward (right in Fig. 16)peripheral face of frame 63 by 'an annular 7 and secured together bybolts, some of which are marked 68. .Within-thejcover and in contactwith its inner "surf race is an annular 'discl69, the perimeter of whichis'groovedt receive anti-frictioninserts 70 that are cemented orotherwise suitably fixed therein and arrang'ed in sets of three at thetop and'bottom'of'the disc; while the side portions of the disc arenotched to receive keys 71, 72, which are bolted to the cover 66 andserve to preventlmovement' of the disc in -a rotary direction whilepermitting .sliding motion. The disc 69 is also formed with 'a circularseries of holes. in which are tightlymounte'dhollow studs, some of whichare marked 73, that are surrounded by expansion coil springs '74.

A ring 75 is fitted over the extremities of the studs, and

the ring isbacked by a series of adjusting rods 76 which are threadedthrough the frame. 63 and, have their protr'uding ends formed for theapplication of an adjusting tool. Flanged collars 77 and 78, fastened bycap screws 8 s free relative motions while automaticallymaintaining ana'deguateseal 'againstj'leakage conformable to the demandsjof processconditions. It should'be added that the springs 74 may be usedasthe'rnain source of pressure while thebellows acts chiefly as aflexible connection.

Turning now to the digesting chamber structure and operation, andreferring particularly to Figs. 1, 1a and 1b, it willj be observed that,generally speaking, it-takes the form of 'a greatly elongated cylinderthat is composed of several sections for construction purposes and also.tojprovide for longitudinal expansion and contracthan under temperaturechanges. The first section 88 which, as above described, is'fianged atits intake end and bolted to annulus 85 (Fig. 16), is of plaincylindrical form and is also'provided with a flange 91 at its oppositeend that "is fixed by. cap'screws to a flange 92 or the like to theforward face of frame 63 and to the opposing face of disc.69, serve toclamp to the said frame and died the extremities of anexpansionand-contraction bellows 79, with the intervention of suitablegaskets, e.g., asbestos. p

The forward face of disc .69 is provided with a circularflange 82 (Fig..18) to which is aflixed by screws, or the like, a sealing ring 83composed of material well adapted to resist chemical action and offer aminimum of friction to mechanical contact movement such, for instance,as a graphite compound, several of which are well known to engineers.smooth surfaced'metallic ring 84, preferably composed of stainlesssteel, that is aifixed, with the interpositioningo'f a suitable gasket,e.g. asbestos, by stud bolts,

This sealing ring mates with a a foundation base 98.

or the like, to a heavy, flat annulus 85, which is firmly secured by alarge number of bolts, some of which are marked 86, to a flange 87 onthe first or intake section 88 of the digesting chamber; a substantialgasket, preferably asbestos, being interposed. A tube 89 is formedintegrally with, or properly secured to, the annulus 85, I

and projects rearwardly (to the left in Figs. '16 and 18) to a pointjust below the safety and control dome 52; said tube serving to lead thematerial being treatedinto the main body of the digesting chamber, andalso to subject theequipment associated with the dome 52 to theconditions prevailing within the digesting chamber.

From the foregoing description it will be evident that rotation of. thedigesting chamber 88 is permitted by the sealing surface contact of thesealing rings 83 and 84; and that the pressure within thedigestingchamber will force the said rings together by acting upon the innerfaces ofthe corrugations of the bellows 79, which are subject tosuchpressure because there is space between the bellows and the tube 89.This pressure will, of course, tend to expand the bellows and, as theframe '63 is rigid, the expansion of the bellowswill slide disc 69 tothe right in Figs.'l6 and 18, and force ring 83 against ring 84. Thiseffect is augmented by the springs 74 which are adjustable with respectto their power. The pressure with which these parts are forced togethershould'be greater than, say by a few pounds, the pressure within thedigesting chamber, to prevent leakage; and the extent of movementimparted by the bellows 79 and springs 74 is limited by contact ofannulus '85 with "an inwardly projecting'flange 90 on cover 66. Endwisethrust is resisted by the rigid base 6, at the inlet end of 1 theapparatus, and by structure at the discharge end of the apparatus whichwill be described later on. The fleXibilit-y'o'f the bellows'79 allowsthe digesting chamber to, withoutbreaking theseal at 83, 84, partake ofwhat maybe described as a circular 'wobbling motion resultantfrom-factors such, .for instance, as the length the digestingchamber.

on one end ofthe second orcentral section 93. The intermediate portionof section 88 is fitted with an ex.- ternaltire 94, whichmay, becomposed of. metal or rubber; and rides upon a pair ofsupporting rollers(see also Fig. 2, which shows a duplication of this structure), onebeingvisible in Fig. 1a and marked 95, suitably journaled in twobearings, one being visible in Fig. 1a and marked '96, adjustably.mounted on rails 97, 97, on Wedges, some of which are marked 99, serveto hold the tire in place; and access to the interior of the section maybe had through removably covered 'ports 100, 101. The-central section93-of the digesting chamber is of extended length (being shown broken inFigs. la and 1b), "and its other or forward end (to the right of Fig.lb) is formed with a flange 102 which is .united bygcap screws with aflange 103 on the adjacent end of the third or discharge section 1040fSurrounding the central section 93 is a spaced jacket or outer shell,which is also shown as broken in the drawings," and consists of threemembers 105,106, 107, fastened'end to end by bolted flanges 108, 109,and 110, 111. The rearward (to the left'in 'Fig. 1a) endof jacket member195 has a flange 112, while the forward (:to the right in Fig. end ofjacket member 107 has a similar flange 113; andbctween said flanges and:flange91 on digesting chamber section 88, and flange 103 on digestingchamber section 104, are positioned two like expansion and contractionjoints 114 and 115,-each .of said joints being formed with a pair 'offlanges 116, 117, and 118, 119, that are bolted to flanges 91, 112, and113, 103, respectively. This provisionallows forlongitudinal expansionand contraction of the: jacket with respect to the digesting chamberunder the influence of variations in temperature. To prevent relativetorque or twist thereof, two circumferential series of'longitudinallyslotted blocks 12!), 121 (see also Fig. 6), arewelded or otherwisesuitably fixed to the exterior of. the central section 93 of thedigesting chamber, one series 'being located near each end; and twocorresponding series of pins 1'22, 123, are threaded through members 105and 107 of the jacket to ride in the slots of'the said blocks and thus,as already indicated, allow relative longitudinal movement whilepreventing relative torque of'the jacket and digesting chamber. Finally,the central member 106 of the'jacket is fastened at its'middle to the.middle of the central section 93 of the digesting chamber (see alsoFigs. ,7 and 8) by a ring 124 that is welded, or otherwise fixed, toboth parts. The said ring is provided with a large number ofperforations 125 to-permit flow of heating steam therethrough "as-will'be later-explained. If "deemed'necessary or desirable thisfastening means may be repeatedat another point or other points. Analternative form of fastening means'is illustrated in Figs.

9 and 10, in which a non-perforated" ring 126 is" welded tobothparts'andi through the digesting cham'ber'wall,

19 valves 129, 130, may be fitted in the said pipes'to control the flow.

The tire unit 9498 hereinabove described as associated with section 38of the digesting chamber is repeated in association with section 104,where the tire is marked '131; the supporting rollers (see Fig. 2) 132,132; the bearings 133, 133; the rails 134, 134; and the foundation base135. A generally similar, but somewhat different, unit is alsoassociated with the central member 106 of the jacket, Where the tire 136has beveled edges and rides on horizontally disposed discs 137, 137,which are mounted on bearings 138, 138, carried by rails 139, 139, on afoundation base 140.

As previously indicated, the digesting chamber is rotatable, and drivingmeans for rotating the same, together with its jacket, during thedigesting treatment, consists (see Fig. la) of an appropriate variablespeed electric motor 141, mountedon a stand 142, and connected by a belt143, or the like, and cooperating pulleys, with a shaft 144 that isjournaled-in bearings 145, 146, and has fast thereon a pinion 147, whichmeshes with a ring gear 148 that surrounds jacket member 105 and issecurely fastened thereto in any proper manner, as by a standard kilngear drive connection which is Well known to engineers. The stand 142and bearings 145, 146, are supported by a common base 149.

For the purpose of heating thematerial being treated within thedigesting chambenthereis provided a main steam inlet pipe 150 (see Figs1b and which is axially disposed with respect to the chamber and'extendsfrom the forward part of section 93 through section 104 and thedischarge portion of the apparatus; bearing supports for the said pipebeing-embodied in structure to be hereafter described. The inner end ofpipe 150'is closed and four branch pipes, two of which are shown andmarked 151, 152, radiate therefrom and pierce the wall isection 93 toestablish communication with the spacebetween the digesting chamber andits jacket. To remove the condensate which collects in the lower portionof the steam space, four stud pipes, two of which are shown and marked153, 154, pierce and project from jacket member 107, and are coupled tofour longitudinally extending exterior pipes, two of which are shown andmarked 155,

' 156. Said last named pipes are coupled to four poppet valves, two ofwhich are shown and marked 157,158, which valves, in turn, are coupledto four radially disposed pipes, two of which are shown and marked 159,160, that pass through the wall of digesting chamber section 104, andenter a sleeve pipe 161, which iss'omewhat larger than andconcentrically surrounds steam inlet pipe 150, and leads to a drainageoutlet 162 for the condensate that may be connected to a steam trap,dump, or other desired form of receiver, not shown. The inner end ofsleeve pipe 161 has a leak proof contact with steam inlet pipe 150 toprevent emission of the condensate into the digesting chamber, and thesaid sleeve pipe has bearing supports which will be identified later on.The poppet valves 157, 158, and the two like ones which are not shown,are normally held closed by springs embodied therein, and a device isprovided for momentarily opening each valve as it approaches its lowestpoint in the rotation of the digesting chamber and its jacket. The saiddevice consists of a shoe 163 having a curved upper surface (see Fig.11) which is adjustably mounted on foundation base 135, and adapted forcontact with a roller 164 carried by each valve, the said contactserving to compress the valve spring and hold the valve open while shoeand roller are in contact. By this arrangement, loss of steam throughthe other valves is obviated because they are held closed by theirsprings. It will be evident that the discharge of the condensate can beregulated by' variations in the size of pipes and valves, the length andshape of the shoe 163, and the rotative speed of the digesting chamber;such regulation being apt to be called for by difiering operativeconditions-relating particularly to the tempera ture and duration oftreatment.

The hereinabove described means for uniting the fixed parts at theintakeend of the apparatus with the rotating digesting chamber, whilemaintaining asubstantially perfect seal, is duplicated for uniting thechamber with the fixed discharge parts, and, as the said means which isenclosed within the cover 66 has been explained in detail, it is deemedsufiicient merely to identify the cover at the discharge end whichcorresponds to cover 66 by the reference numeral 165, and note that ithouses -a structure like that within cover 66;

Similarly, the discharge end of the apparatus embodies a relief andcontrol dome 166, that is like dome 52, and correspondingly'equipped;its vent 167- and rupture diaphragm 168 being shown. This dome 166 isflanged at its lower end and bolted to a flanged collar 169, thatuprises from a discharge chamber 170,- which is welded to or formedintegrally with an annular frame 171, that is bolted to' cover 165,andalso stands upon a sturdy support 172, resting'on a foundation 173.The dome 166, like dome 52, is shown broken as to its height, and itshould be noted that the relative heights of these two domes may vary inconformity with conditions of the particular process for which theapparatus is being installed. They may be of equal height or either onemay be higher than the other. J

:The discharge chamber 170 has a co-axial extension 174 bolted thereto,as-indicated at 175; the said extension being formed with an annularwall 176 reinforced by webs, two of which are shown and marked 177, 178.Longitudinal thrust resisting beams 179, 180, are rigidly bolted to thesaid wall 176, the beams being of I shape in vertical section, as shownin Fig. 5, and having a wide lateral extent, as shown in Fig. 2, wherebytheir ends may be embedded in rigid building walls, e,g., masonry. Thisstructure is very effective in withstanding the thrust generated bypressure within the digesting chamber, and complements the rigid baseconstruction at the intake end of the apparatus which has hereinabovebeen explained. an added precaution, the apparatus is equipped withelectric set-upfor automatically stopping the drive motor 141 in casethe longitudinal thrust results in movement exceeding the designed limitat either end ofthedigesting chamber. This set-up is represented in thewiring diagram of Fig. 23 with appropriate inscriptions; and it will beseen that a limit switch connected was to break the electric current tothe drive motor will be activated by the fiange87 on section 88 of thedigesting chamber and/or by the corresponding flange (not shown) onsection 104, in the event of more than designed longitudinal move mentby either or both sections.

The condensate drainage outlet 162 is formed ina cast ing 181 that isfastened by cap screws to a centrally apertured square plate 182 boltedto beams 179, 180. The casting 181 has a horizontal bore surrounded by aflange 183 to which is bolted a flangedbracket 184 that is likewiseformed with a bore and is developed at its extremity into an inlet 185for live steam, which inlet is provided with a flange to assist incoupling a source of steam supply (not shown) thereto. The open end ofthe main steam inlet pipe 159 is adjacent inlet 185, and the said pipefinds packed bearings 1-86, 187, in the bores of bracket 1'84 andcasting 181; while the condensate discharge sleeve pipe 161 has similarbearings 18%, 1 89, in the inner peripheral edge of casting 181 and inthe wall 176 of discharge chamber extension 174. A tube 199 surroundspipe 161 within the said discharge chamber, having its ends supported bythe said wall 176 and an annular partition 191 within the dischargechamber 170.

The discharge portion of the apparatus is shown as to its generalarrangement at the right side of Fig. 1b, and in Fig. 2, while itsconstruction is set forth in Figs.l9-2 2, and will now be described. V

The discharge chamber 170 is formed in'its lower por presser 220, whichis highly. desirable.

' erable shut oif valve 197 may, if desired, be fitted in'the duct 194in order to close the same and isolate the discharge valve for thepurpose of maintenance and adjustment. Thebottom of the funnel also aflange198 that is fixed by stud bolts or cap'screw's'to the annularcover 199 ofthe discharge valveunit The discharge valve proper 200 is ofthe volumetric type and provided with the usual peripheral series ofbuckets 201. 'It is keyed, or otherwise suitably fixed, to a shaft 202,the ends of which aremounted in ball bearings 203, 204, that are fittedin journal boxes-205, 206,1having removablecovers2'07, 208; thesaid'boxes' being secured by cap screws, four of which are shown andmarked 209, to the valve housing 210 and its side cover 211 that is,

in turn, fixed to the housing bycap screws, two of which arelsho'wn andmarked 2121 The end of 'the shaft sup portedby bearing 204 protrudesfrom bearing box 206 through cover 8and has a sprocket 213 first thereonwhich meshes with a chain 214 that also meshes with a smaller sprocket215 (Fig. 2)which is gear driven from a variable speed electric motor216. The housing 210 is flanged at its top and securely-fastened tocover 199 Mountedfor' vertical slidablemovement within the housingis asaddle 218 which rests upon the volumetric valve 200 and is eurved toconform thereto. The saddle,

is formed with'a downwardly tapered opening the lower arethreadedthrough the'cover 199 and have their lower ends fittedin a presser 2 20which rests-on the top of saddle 218. Expansion coilv springs 221surround the rods 219-and are'confined between the presser 220andcolla'rs 222 formed integrally with or fixed, asby pins, to the rods.The upper ends of the rods are squared for the application ofanadjusting tool, and they are enclosed within caps. 223 that uprise' fromthe cover 199, being cast therewith or aflixed thereto, and are fittedat their tops with sealing screw 'plugs 2.24. It will be evident that,by removing the plugs and turning the rods' 219, the pressure of springs221 can be varied, while the replacement of the plugs will seal theparts against leak: age of pressure from the housing 210. A bellows 225is positioned between the cover 199'and the presser 220,

and held in place by a pair of containing rings 226, 227, which arefastened by bolts or screws to the cover 199 and presser 220,respectively, and clamp the extremities of the bellows therebetween. thebellows constitutes a connectionbetween the funnel 196 and the saddle218 for the passage of the treated material which is beingdischarged,,and that the pressure from the digesting chamber that existsthe bellows will tend to expand the latter and thereby unite with thesprings 221 in forcing the saddle against the volumetric valve 200. Thebellows also provides flexibility'in' the connection between the cover199 and .the

' To improve the sliding contact between the valve and the saddle byrelieving the friction engendered by the force of the bellows andsprings, the saddle is preferably provided with an anti-friction facing228, that may be composed of, for instance, graphite or graphiticcarbon; or the facing may consist of an inert low friction plastic,orlthe like. The vertical movement of the saddle may likewise bebettered by making it in the form of an iron while-the housing 210 is ofsteel, with or without the'interpositioning of a'lining 229 composed ofsome Uta ' by a large number of bolts, some of which aremarked,

It will thus be clear that 12 material suchasstainless steel. Theprecise nature of the materials employed will naturally be dictated bythe factors of chemicals, temperatures, and pressures involved in thetreating-process for which the apparatus is designed.v s f It will beevident, that the cooperation of the valve 200 and saddle 218 enableseach bucket of the valve to receive and carry along its capacity oftreated material as the valve is rotated, and"that, when each bucketreaches the lowermost point'of. its travel, its contents will be,dumpedinto the' outlet 230 of housing 210, for finishing treatment'orfurther-digesting treatment as desired, which need not be described foran understanding of this invention. Thus, with the cubical size of thevalve buckets being known, the valve'may be rotated at such speed asdefinitely to control the rate of discharge of the *material. For'thepurpose of inspection and cleaning, an opening in the. housing 210having a cover plate 231 is provided, and additional openings may bepositioned at other .points if desired.

The modified form of the invention exhibited in Figs. 4, 4a and 4b,difie rs' from the form already described mainly in that there is noheating jacket surrounding the digesting chamber, which, of course,requires certain changes with respect to the sup plyingof heating steamto the materialbeingtreated. is preferably'accomplished byentirelyeliminating' the steam supply piping with its supports, 'oftheiacketed form, and merely injecting steam through the vents and 167of the domes 52 and 166, respectively, ,it being advantageous to usesteam of a higher temperature at'the vent 'l67 owing to the desirabilityof greater .heat in the later stage of the process. The means forremoving condensate is also omitted from this modified form, because thecondensate "with the material under treatment and is discharged-therewith. The absence of the steam supply and condensateremoval pipes obviates the necessity for a large part of the structureat the discharge end of the apparatus, and permits the forward '(to] theright in Fig. 4b) end'of the discharge chamber 170 to be connected bybolted flanges 232 to a curved duct 233 of gradually reducingcross-section that is flanged and bolted" directly to the cover 199 ofthedischarge valve unit which is the same as that of the'jacketed formof theinvention. :A thrust resisting beam 234 is integral with duct 233,and the lower part of the discharge chamber 170 is formed witha'drainage and cleaning'collar 235 and cover 236 like theparts 61 and 62of the other form. This unjacketed embodiment is less expensive toconstruct but it lacks the desiderata of eliminating the dilution andcon tamination of the material being treated bythe injection of steamthereinto; and of being'able to 'use heating steam at lower pressurethan that within the digesting chamber; as well as others inherent inthe characteristics of the jacketed structure. 7

With reference to both forms of the invention, the digesting chambermay, if desired or it is'deemed advisable, be reinforced againstdistortion in the direction of either collapse or expansion by theprovision ofbands welded, or otherwise properly alfixed, to the exteriorthereof, such as the bands shown in dotted lines 'and marked 237 inFigs.la and lb.

, Again referring to both the jacketed and unjacketed forms of theinvention, it should be pointed out that, although not shown in thedrawings, the apparatus is usually so mounted and arranged that thedigesting chamber declines at'a' slight angle from the intake end to thedischarge end, a drop of one-sixteenth to one-quarter of an inch perfoot of length having been found 'to be satisfactory; the purpose beingto facilitate movement or" the material being treated through theapparatus, and also .to aid in evacuation of the steam condensate in thecase of the jacketed chamber. However, the characteristics or conditionsof some procedures may dictate a horizontal or even slightly inclinedarrangement of the 13 chamber, and the apparatus is equally suitable tosuch positioning.

In Fig. 24 is represented an added feature which may be adopted in theconstruction of either or both embodiments of the invention. It consistsin a helix, screw or worm that may be installed within the centralsection 93 of the digesting chamber in order to compel the materialundergoing treatment to travel a winding or spiral course or path,thereby notably lengthening the travel without requiring elongation ofthe chamber. In this figure of the drawings the central section 93 ofthe digesting chamber is so marked, while the helix, screw or worm isindicated by 238. It winds around and is secured, as by welding, to ahollow core 239, and its spiral peripheral edge or rim is likewiseattached to the inner wall of the chamber at the inlet end or throughoutall or part of its length, as desired, so that the screw or worm rotatestherewith. The flights or individual spirals are formed with notches240, which are of value in permitting escape of air and gases by ventingthrough either or both domes 52 and 166. These notches will naturallyallow some of the solid material to travel along the chamber withoutfollowing the spiral path, but this will be small in amount and willpractically cease as soon as the chamber is filled.

A further modification of the invention is illustrated in Figs. 25-27,where the unjacketed digesting chamber form of the apparatus is fittedwith connecting means for tying together the inlet and dischargestructures to augment their ability to withstand the powerfullongitudinal thrust generated during operation by the pressure withinthe digesting chamber. As these figures repeat to a large extent theshowings of Figs. 4-4b, the repeated parts will neither be described nornumbered except as they are involved with this modification of theinvention. The connecting means comprises a suitable number, three beingshown, of tubular tie rods 241, 242, 243, which are longitudinallydisposed at 120 intervals around the exterior of the digesting chamber,and preferably in the path of an imaginary circle concentric with theaxis thereof. The said tie rods are provided at their ends with flanges,welded or otherwise properly secured thereto, which flanges are boltedto mating flanges as indicated in part at 244, 245, 246, 247 and 248;which mating flanges are likewise secured to butts, some of which areshown and marked 249, 250, 251 and 252, that are welded or otherwisesuitably fixed to pairs of anchor lugs, some of which appear and aremarked 253, 254, 255, 256 and 257; the said anchor lugs being, in turn,fast, as by welding, to the rigid covers 66 and 165 that constituteparts of the inlet and discharge structures respectively. The butts onthe anchor lugs are spaced equal radial distances from the longitudinalaxis of the digesting chamber, so that they may be said to be, as agroup, ccncentric with the chamber. It will be clear that the tie rodswill tensionally resist thrust stresses occasioned by operationalpressures within the digesting chamber and thereby maintain the endstructures of the apparatus in operating position.

As the tie rods 241, 242, 243, are of considerable length, intermediateportions thereof find support in two triangular trusses, which aredenoted generally in Figs. 25 and 25a by 258 and 259, and are based onsolid foundations, e.g., concrete, 260 and 261. Fig. 27 shows the detailof one truss and, as they are alike, it is deemed sulficient to describethat disclosure in which the truss comprises three members united attheir ends in triangular form by webs. Each of the said members consistsof a pair of angle iron or steel elements denoted by 262262, 263-263,264-264, and they are riveted or otherwise properly fastened to the webs265, 266, 267, that are interposed between the pairs of elements, whichlatter are also secured to each other by rivets, or the like, andwashers, some of which are indicated by 268. The webs are formed withopenings that snugly receive en ages the tie rods, as clearly shown inFig. 27; and it will be seen that these trusses which surround thedigesting chamber of the apparatus and are mounted on their ownfoundations constitute means for rigidly supporting the tie rodsintermediate the ends of the latter.

It should be noted that, while this tie rod construction has beendescribed in connection with the unjacketed form of the apparatus, it isequally applicable to the jacketed form.

Figs. 28 and 29 illustrate a second kind of means for connecting ortying together the inlet and discharge ends of the apparatus which meansis particularly adapted to the form of the invention in which thedigesting chamber is not jacketed and is provided with an internalhelix,.worm or screw as is also represented in Fig. 24. The portions ofthe inlet structure of the apparatus shown in Figs. 28 and 29 are thesame as those shown in Fig. 4 and previously described, so they will notbe redescribed or numbered; but it may be desirable to note that thedigesting chamber partially appearing in Fig. 28 is marked 88, and apart of its inlet neck 45, as in. Fig. 4, while the helix, worm orscrew, which difiers somewhat from that shown in Fig. 24, is marked 269,and its hollow core or axis 27 0.

The tying means in this modified form of the invention comprises asingle tubular tie rod 271 that lies within and passes entirely throughthe core 270, from which the ends of the tie rod protrude and are madefast to the inlet and discharge structures of the apparatus, as depictedin Figs. 28 and 29, which are directed to the inlet end. The means formaking the tie rod fast at the discharge end is the same, and so callsfor neither addi tional illustration nor description.

The said means for making the tie rod fast consists of a very strongspider having three radial arms 272, 273, 274, and a hub 275 that istraversed by the end of the tie rod. The hub is welded, or otherwiseproperly fastened, to the arms, and the latter are likewise firmlyafiixed to the inner wall of the inlet neck part 45 previously describedin connection with Figs. 1 and 4. A large nut 276 is threaded on the endof the tie rod and, when screwed tight, bears firmly against the hub275. A conical tip 277 is amxed, as by welding, to the extremity of thetie rod in order to close the rod to the ingress of the material undertreatment and also to facilitate the passage of the material thereby.

This form of end structure tying or connecting means requires nosupports for the tie rod 271 intermediate its ends because the rod lieswithin the hollow core 270 of the helix, worm or screw 269 and thesaid'core is well supported by the flights or spirals of the latter. Itshould also be observed that the tying means, though positioned withinthe digesting chamber, does not at all impede the movement of thematerial being treated because the tie rod is within the core of thehelix, worm or screw; while the ends of the rod are so attached to theinlet and discharge structures, and are so formed, as not materially ornoticeably to hamper material flow. Finally, the resistance of the tierod to longitudinal stresses generated by pressure within the digestingchamber is very efieetive due to its axial positioning; and the tyingstructure is simple and inexpensive.

In the foregoing description occasional mention has been made of thepresence of gaskets or the like; and it should be noted that, whethermentioned or not, such are employed in connection with all joints orconnections where leakage is to be avoided and their use is practical.Similarly, flexible piping may be adopted when called for.

While we have described this apparatus as being used singly, it shouldbe emphasized that it is extremely well suited to tandem arrangementwith a second similar apparatus, appropriate connecting structure beinginterposed, as set forth, for instance, in U.-S. Patent to De la Roza,Sr., No. 2,542,801, dated February 20, 1951, whereby the treatment maybe continued in two stages,

e.g., aqueous treatment, with or without added acid, followed byalkaline treatment. Indeed, if contemplated procedure should so dictate,more than two of the apparatus may be hooked up to accomplish treatmentconsisting of more than two stages, e.g., neutral, acid and alkali.

As the functioning of the several parts, and subassemblies of parts, hasbeen set forth in connection with their mechanical description, and asthe invention is directed to apparatus rather than process, and as it isadapted to use in various forms of digesting procedures, there isthought to be no call for a general summary of the operation of theapparatus. However, it may be of some importance to observe that thisinvention is especially well fitted for digestion treatments whichminimize the degradation of the cellulose, particularly at elevatedtemperature, while preserving the purity, strength and other desiredcharacteristics of the final product, and maintaining a high yield.

We desire it to be understood that various changes may be resorted to inthe form, construction, arrangement and material of the parts of theapparatus without departing from the spirit orscope of the invention;and hence, we do not intend to be limited to details herein shown ordescribed except as they may be included in the claims or be required bydisclosures of the prior art.

What we claim is:

l. Apparatus designed and adapted for continuous procedure in thedigesting treatment of cellulose bearing material for the separationfrom the cellulose of foreign substances associated therewithcomprising, a digesting chamber, a spaced jacket surrounding at leastpart of the chamber, means for supplying a heating medium to materialfor the separation from the cellulose of foreign substances associatedtherewith comprising, a digesting chamber, a spaced jacket surroundingat least part of the sides of the chamber, means for supplying a heatingmedium to space between the chamber and the jacket, means rotatablysupporting the jacket, and means for rotating both'the chamber and thejacket around their longitudinal axes, said means for supplying aheating medium'to space between the chamber and the jacket includingpipes axially and radially disposed with respect to the digestingchamber.

4. Apparatus as defined in' claim 3, which also includes means forremoving condensate of the heating medium'from space between the chamberand the jacket embodying pipes axially and radially disposed withrespect to the digesting chamber, the axial pipe of the condensateremoving means surroundingthe axial pipe of the means for supplyingheating" medium.

5. Apparatus as defined in claim 4, in which the means for removingcondensatealsoembodies pipes carried by the jacket exteriorly thereofand connecting spacebetween the chamber and the jacket with the radiallydisposed pipes of-the means for removing condensate.

16. Apparatus as defined in claim 5, which also includes normallyclosedvalves positioned in the said pipes carried by the jacketexteriorly thereof. '7. Apparatus as defined in claim 6, which alsoincludes fixed means in the path of rotation of said valves fortemporarily pening them seriatin'i. a

8. Apparatus as defined in claim 7, which also includes 1 1b means forvarying the duration-of theopen valve periods.

9. In apparatus designed and adapted for continuous procedure in thedigesting treatment of cellulose bearing material for the separationfrom the cellulose of foreign substances associated therewith and havinga rotary digesting chamber, fixed means for the passage of the materialinto the chamber and fixed means for receiving treated material from thechamber, means connecting at least one of said fixed means with thechamber to permit relative rotary motion thereof and circular wobblingof the chamber while maintaining a seal against leakage therebetween,said connecting means including the combination of a complementary pairof sealing elements, one being fixed and the other rotatable, and adevice subject to pressure within the digesting chamber forpressing saidsealing elements together.

l6. Apparatus designed and adapted for continuous procedure in thedigesting treatment of cellulose bearing material for the separationfrom the cellulose of foreign substances associated therewithcomprising, an elongated rotary digesting chamber, a hollow core locatedcentrally therewithin and extending lengthwise of the chamber, andspiral means secured to the outer wall of said core and the inner wallof said chamber. adapted to compel material being treated to travel anelongated spiral course through the chamber between the core and theinner wall of the chamber, the said spiral means being provided withopenings at its outer circumference to form spaces which permit thepassage of gas but not solids in a direction toward either end of thechamber.

11. Apparatus designed and adapted for continuous procedure in thedigesting treatment of cellulose bearing material for the separationfrom the cellulose of foreign substances associated therewithcomprising, a digesting chamber, a spaced jacket surrounding at leastpart of the chamber, means for supplying a heating medium to spacebetween the chamber and the jacket, means rotatably sup porting thejacket, means for simultaneously rotating both the chamber and thejacket, means interconnecting the chamber and jacket which fixes themagainst relative rotary movement while providing for limited relativeaxial movement, and automatic means for removing from space between thechamber and jacket condensate of the heating medium collected therein,said last named means comprising a fixed contactor having an elongatedcontact surface and a spring biased valve carried by the jacket andconstructed for coaction with the said contactor to open the valve andbriefly hold it'open;

12. In apparaus designed and adapted for continuous procedure in thedigesting treatment of cellulose bearing material for the separationfrom the cellulose of foreign substances associated therewith and havinga rotary digesting chamber, fixed means for the passage of the materialinto the chamber andfixed means for receiving treated material from thechamber, means connecting at least one of said fixed means with thechamber to permit relative rotary motion thereof and circular wobblingof the chamber while maintaining a seal against leakage therebetween,

, said connecting means including the combination of a complementarypair of sealingelements, one being fixed and the other rotatable, and adevice subject to pressure within the digesting chamber for pressingsaid sealing elements together, the said means for the passage of thematerial into the chamber comprising, an inlet leading toward thechamber and provided with an opening for the ingress of the material anda heroin its wall, and a piston mounted to reciprocate within the borefor urging the incoming material through the inlet, the bore beingslightly larger in circumference than the circumference of the piston topermit the pass-age through .therebetween of liquid squeezed from thematerial by the piston while preventing the passage through of solidstherebetween;

13. Apparatus as defined in claim 12, in which the cross sectional areaof the said material inlet increases in size between the said ingressopening and the chamber.

